Time-limit control for circuit-breakers.



C. S. VAN NUIS.

TIME LIMIT CONTROL FOP. cmcun' BREAKERS.

APPLICATION FILED FEB.19, 1909.

Patented Sept. 1, 1914.

4 SHEETS-SHEET 1.

Inventor Witnesses Attorneys.

C. S. VAN NUIS. TIME LIMIT CONTROL FOR CIRCUIT BREAKERS.

APPLICATION FILED 11113.19, 1909.

Patented Sept. 1, 1914.

4 SHEETS*SHEET 2.

mm m m5 M WM Witnesses 51M Attorneys.

0. s. VAN NUIS. TIME LIMIT CONTROL FOR CIRCUIT BREAKERS. APPLICATION FILED PEB.19,1909.

1,109,091 Patented Sept. 1, 1914.

. A QHEKTSSHEBT 3.

I 6 19 J? A k I 35 j Witnesses /Z [:wentor 9M (Z1044 J) Am )701 5 [11/ Attorneys.

G. S. VAN NUIS.

TIME LIMIT (JONTBOL FOIL CIRCUIT BREAKERS.

APPLICATION F1LED FEB.19,1909.

Maj/LA pun fil m M9 14 1 0 Attorneys.

CHARLES S. VAN NUIS, OF NEW BRUNSWICK, NEW JERSEY.

TIME-LIMIT CONTROL FOR CIRCUIT-BREAKERS.

Specification of Letters Iatent.

Patented Sent. 1, 1914.

Application filed February 19, 1909. Serial No. 478,862.

To all whom it may concern:

Be it known that I, CHARLES S. VAN Now, a citizen of the United States, and a resident of the city of New Brunswick, county of Middlesex, State of New Jersey, have invented a new and useful Time-Limit Control for Circuit-Breakers.

The object I have in view is the production of a device to use with or form a part of a circuit breaker or other emergency protective device, having a time limit for the automatic protection of the electric circuit for certain current densities.

The particular object I have in view is to produce an apparatus, which will actuate the breaker or cut out only upon a certain lapse of time after the overload has occurred.

These and further objects will appear in the following specification and accompanying drawings considered together or separately.

In the drawings: Figure 1 is a diagram of a coil and two cooperative armatures in normal load position. view, showing the parts in overload position after the lapse of a predetermined time.

Fig. 3 is a plan view of a device, embodying my invention. Fig. 4 is a sectional View of the same on the line 44 of Fig. 3. Fig. 5 is a front elevation of the complete device. Fig. 6 is a section on the line 6-6 of Fig. 3. Fig. 7 is a developed view, showing a section on the line 77 of Fig. 8; and Fig. 8 is a section on the line 88 of Fig. 7

In all of the views, like-parts are designated by the same reference characters.

In the embodiment of my invention set forth in this application, I utilize a magnetic field, which is induced b current in the electric circuit which is to protected, such field influencing two movable armatures. The movement of one armature is governed by a retarding device, and the action of the second armature, for a current value not exceeding a given maximum, is dependent upon the relative positions of the two armatures, and the magnetic circuit in which they are suspended. The movement of the second armature is made to render operative the controlling mechanism installed in the circuit to be rotected either by direct action or through t e intermediary of a relay. The positions of the two mov- Fig. 2 is a similar able armatures in relation to each other and the magnetic circuit in which they are susnded are designed to be such as to give, in addition to the above function, an insta'nt/aneous action of the second or engaging armature when the current value of the protected electric circuit reaches an excessive amount, as in the case of a short circuit or unusual overload.

Figs. 1 and 2 diagrammatically re resent the arrangements of the coil and the two armatures. 1 is the coil which forms a part of the circuit to be protected. 4 is an armature in such coil, the movement of such armature being controlled by the retarding devices I). 9 is a second or actuating armature which, through the agency of the rod 16, engages with and actuates the tripping mechanism a of the circuit breaker installed in the main circuit. Fig. 1 represents the parts in normal position, the second or actuating armature 9 being just within the field, and the first or primary armature 4 lying well within the field. On the occurrence of excessive currents in the circuit to be controlled, the coil 1, which is connected in said circuit, will be sufliciently energized to produce a magnetic field which will attract and move the armature 4 against the counterforce of the retarding devices I). As the armature 4 moves farther and farther into the coil 1, the permeability of the magnetic circuit increases and the armature 9 is more and more strongly attracted until it begins to rise. It is apparent that as the armature 9 moves upward, its movement will become more and more rapid, and that the rod 16, attached to said armature, will strike with considerable force the tripping mechanism a of the circuit breaker.

My invention may be embodied in various structures, but I have illustrated in Figs. 3 to 8 inclusive my preferred embodiment. Referring to Fig. 6, 1 is a coil in series with the circuit to be protected, supported on the base or switchboard 2 (Fig. 3) by the stud 3, the free end of the coil being directly connected to one of the circuit breaker terminals, if desired. The primary armature 4 is formed of soft iron and is hollow. Its upper end is enlarged at 5, and engages with and is supported by a steel ring 6. This ring has two projecting ears 77 (Fig. 4), each ear having a depression formed in it to receive the hardened point of one of two cone pointed screws 8. 9 is the second or actuating armature, also made of soft iron. This armature is supported by and contained within a thin brass tube 10, in which it may move freely. The tube 10 has a brass bottom 11, to prevent sticking of the armature,

and it also has an enlarged upper end 12 (Fig. 6), by means of which the tube 10 is supported in the flattened end 13 of the bracket 14 (Fig. 3). The tube 10 is further maintained so that its axis is coincident with that of the coil 1, by an insulating bushing 15 which is clamped to the tube. The armature 9 is made hollow, except at its bottom which is closed, and carries an engagement member 16, which is loosely attached to it by a pin 17. The engagement member 16 is made of a light tube of brass or aluminum and is topped by a fiber buffer 18. This buffer is adapted to engage with the controlling mechanism a, which is installed in the main circuit of which the 601i 1 is a part. A suitable bushing 19 lies within the tube 10 to act as a guide for the upper end of the member 16. The armature 4 is supported by floats 20, through the medium of the equalizing bar 21, and its attachments. The bar 21 is best made of an aluminum casting and is adapted to receive the adjustable pivot screws 8, with their lock nuts 22 (Fig. 4), about the middle of its length. The retaining arches or staples 23 (Figs. 3, 4 and 5) loosely unite the parts 21 and 7, permitting the proper amount of motion, yet preventing the separation of the parts. The ends of the bar 21 are forked and in the forks are pivotally connected two steel tipped aluminum tubes 24 by means of the steel projection 25 and pivots 26. The tubes 24 have bearings on the iron bottoms 27 of the floats 20 through the steel pivot point 28 (see Fig. 8). The liquid used in the ap paratus for supporting the floats 20 should be of high specific gravity so as to impart great buoyancy to the floats, and it is de sirable that its mobility should change but little with varying temperatures to the end that there may be small variation in regula* tion. lVlercury has proven satisfactory in tests, and this liquid will be considered in the further description as the medium for obtaining the time element sought. This accounts for the exclusion of all metal ex cept iron from the reservoir. However.

other liquids might be employed, for in stance, an oil with a small percentage of viscosity. In this case much of the metal might be other than iron. The liquid is contained within a reservoir 29, which, when mercury is used, should be of iron. The floats 20 should be of thin lIOl'l covered with a fiber tube 20 to essen the magnetin action .so formed that it can best be made of wrought iron, curved to shape to inclose the coil. The reservoir may be drilled at 30 before it is curved, a tight plug 31 closing the cavity and making it purely internal and long enough to unite the two buoyancy chambers 32 and 33, giving the liquid a free passage between them (see Fig. 8). Other vertical chambers, 34, 35, 36, 37, 38, 39 and 40, may now be drilled of varying depths and for different functions, as will nereinafter be described. Each of these chambers are united to the next adjacentone below the liquid level, except in the chambers 32 and 33, which are connected to the chambers 34 and 35 respectively by overflow grooves 64 and at their top extremities, which afl'ord relief outlets for excess liquid in the buoyancy chambers 32 and 33 at times of excessive overload on the electric circuit, as hereinbefore explained. For the purpose of uniting the intermediate chambers, 34, 35, 36, 37, 38, 39 and 40, I drill transverse holes 41 between the chambers to break down the intervening walls, thus forming a multichambered reservoir (as is shown in Figs. 7 and 8). The outer ends of the holes 41 are closed by means of tightly fitting plugs 42. For the purpose of providing a slow outlet from the buoyancy chambers 32 and 33, I connect the chamber .40 to the transverse chamber 30 by a small passageway 43. At the upper end of this passage is a regu lator 44 in the form of a needle valve. This regulator may be operated by the handwheel 45 and stem 46, which is threaded into the cap 47, which covers the reservoir and is secured thereto by the screws 48. For the purpose of providing a quick outlet from the chambers 32 and 33 into the reservoir chambers, the openings 64and 65 are made, as hereinbefore mentioned. A longitudinal slot is cut into the chamber 40 and a glass tube 50 (see Fig. 5) is inserted therein and properly packed to prevent leakage. On the outer surface of the reservoir, which may be flattened at this point, is placed a graduated scale 51 which will indicate the liquid level for different current values. A quick inlet to the buoyancy chambers 32 and 33 is efl'ected b a ball valve 52 (Fig. 8), the retainin c amber and seat for which are provi ed in the member 53, which is located at the junction of the chambers 30 and 39. A pin 54 serves to keep the ball in the retaining chamber. One or more of the chambers 34, 35, 38 or 39 may be equipped with a governing float 61 which may be of a ma- 'terial and slze adapted to rise and fall freely with corresponding fluctuations of thelevel of the liquid supporting them. These governing floats are each provided with an adjustable stem 62 and lock nuts 63, the stem being intended to check the upward travel of the float at any predetermined position by impinging against the cap 47 -Having assembled the apparatus as described, as much liquid (as mercury) is introduced into the reservoir as is needed to give the floats 20 a force of buoyancy upward against the ends of the equalizing bar 21, just suflicient to overcome the downward pull of the armature 4 on said equalizing bar due to the wei ht of said armature and the magnetizing e ect of the coil 1 when normal current is passing therethrough. When the current in the coil 1 has increased to-a critical point, such current will create a magnetic field of suflicient strength to attract the armature 4 downwardly; and when a considerable portion of its travel is accomplished, the effect of the additional iron so rought Within the magnetic circuit will cause the armature 9 to rise rapidly into this stronger field and the engagement member 16 to be brought into operative engagement with the tripping mechanism 1n the customary manner. The retarding efl'ect upon the descent of the armature 4 is accomplished by allowing small clearance for the floats in the buoyancy chambers 32 and 33. If the end areas of the floats 20 are greatly in excess of the clearance areas, then any depression of the floats will give an exaggerated increase in the height of the column of liquid, increase the buoyancy and restore the equilibrium of force which is automatically maintained until enough liquid has passed from the buoyancy chambers 32 and 33 through the passageway 43, and through the controlling valve 44, to permit the armature 4 to complete the required portion of its travel. The regulated speed of travel of the armature 4 will be uniform for all current values and the time element will be nearly so. When a total or partial release of magnetic pull occurs during the downward travel of the armature 4, the floats 20 will rise and a sudden fall of liquid will follow in the chambers 32 and 33 which will be immediately compensated for by the unseating of the ball valve 52 and the consequent restoration of the liquid level in the reservoir and buoyancy chambers. It follows, therefore, that a slow descent and quick rise of the armature 4 will occur after sudden current fluctuations in the circuit, thereby making the time element always fully available.

The device may be adjusted in various ways. It is evident that as the armature 4 descends into a stronger magnetic field a stronger force is applied to it, but a similar travel of the attached floats 20 gives an increasing displacement, thus exerting a counter force. If the value of the former is known for a given current value, the latter may as nearly ofl'set this as may be desired, by properly proportioning the sectional area of the reservoir to that of the floats 20. For the purpose of preventing too rapid downward movement of the armature 4, I provide the floats 61. These floats 61 (of which there may be as mary as necessary or desirable) will, when they rise and engage with the cap 47, reduce the clearance space in which the liquid can ascend in the chambers 34, 35, 38 and 39; thereby, when the liquid finds its level by seepage through the valve 43, the displacement of the floats 20 will have been increased. The floats 61 float upon the surface of the liquid and are free to rise 'until the screw pin 62 comes in contact with the cap of the chamber. As they rise and fall with the liquid they do not affect the latter. When they come into contact with the cap, however, and the liquid rises, it is apparent that, in each chamber in which there is a float, the free space in which the liquid can rise is very much reduced, as the liquidto rise highermust pass around the float. If there be a number of these floats (there being places shown for four floats), it is ap parent that, when all are in contact with the cap 47, the room for the liquid to rise in these vertical chambers is exceedingly small,hence a slight increase of displacement in the buoyancy chambers will cause a greater increase in liquid elevation in all chambers, when equilibrium is established, and will exert a correspondingly greater force of buoyancy per unit of travel of floats 20. The length of the stems 62 on the floats 61 may be adjusted in the factory, and, as they are entirely inclosed within the reservoir, they cannot afterward be tampered with. The increased force that such (lisplacement will effect may be determined by the number, size and shape of the floats 61. By making them conical. spindle shaped or hour-glass shaped, the characteristic of the curve of adjustment can be determined within very narrow limits. The advantage of employing the floats 61 is that the apparatus may be used under varying conditions, with a standard shape and size of reservoir. By these means apparatuses may be adjusted to suit all occasions as to the amount of over-load and time limit.

It should be remembered that the force of the magnetic field upon the armature 4, at any point of its travel and for any number of amperes within the range of the instrument, should exceed the force of buoyancy upon the floats 20 when the liquid level in the reservoir is the same as in the chambers 32 and 33.

The apparatus may be regulated as desired. It is apparent that the main magnetic gap between the-two armatures is nonadjustable and regulations for different current values must therefore be effected in some other manner, and it is best done by varying the suhmer ence of the floats 20 to the extent indicated for such values on the graduated scale 51. The regulation of the level of liquid is accomplished by displacement pistons 55, 56, carried in the chambers 35 and 37 respectively and controlled by hand wheels 57, 58 on their threaded stems. 13y lowering one or both of the pistons 55 and 56 into the liquid, its level will be raised, and the displacement of the buoyancy floats 20 will be increased. The level of the liquid will show through the glass 50 and the scale 51 may be indicated accordingly. The scale will show the over-load necessary to move the armature 4 at levels of the liquid, which appear through the glass 50 adjacent to the scale. The only other regulation required is that controlling the time element and this is effected by the hand \vhee 4-5 operating the needle valve, which controls the extent of opening of the aperture 43.

I t will be apparent from the foregoing description that my device will operate an emergency device, such as a circuit breaker, under two conditions. The first condition will be when the circuit is subjected to an overload, which will cause injury only when continued beyond a certain lapse of time. The second will occur when an ove'rload of excessive or destructive amount occurs, whereupon the emergency device will be actuated without lapse of time. The first condition will cause the armature 4 to be gradually drawn into the magnetic field of the coil 1 against the resistance of the retarding device. As the armature 4 enters the field, the permeability of the magnetic circuit is increased until the armature 9 is so strongly attracted that it rises and carries with it the tube or rod 16 which actuates the emergency mechanism. It is to be noted that if the overload is large, the equalizing of the liquid in the chambers 32 and 33 may take place through the openings 64 and 65 as well as through the valve 43, thereby permitting quicker operation of the relay with large currents than with small. Under the second condition, a magnetic field of sufficient intensity will be instantly created to attract the armature 9 immediately even before movement of the armature' l has taken place. It is apparent, therefore, that the device will protect a circuit both from harm arising from overload conditions which are injurious only if prolonged, and from harm due to momentary excessive and quickly destructive overloads. Another advantage of my device is that the actuating armature 9 remains at rest until the magnetic field is sufiiciently built up to lift it, and then moves quickly to its upper position, causing the tube or rod 16 to come into engagement with the emergency mechanism a, with sufiicient force always to insure the operation of said mechanism. This permits the employment of a small time-limit device with a relatively large circuit-breaker or other emergency device.

In accordance with the provisions of the patent statutes, I have described the principle of my invention together with the apparatus which I now consider to represent the best embodiment thereof; but I desire to have it understood that the apparatus shown is merely illustrative and that the invention can be carried out in other ways.

Having now described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. A time-limit device comprising an actuating magnet coil, an armature cooperating therewith, and a retarding device cooperating with said armature comprising a float connected to said armature, a chamber containing liquid in which said float operates, a reservoir connected to said chamber through a. restricted passage, a check valve in the connection between said chamber and said reservoir permitting free flow of the liquid only from said reservoir to said chamber, and an overflow connection between said chamber and said reservoir.

2. A time-limit device comprising an actuating magnet coil, an armature cooperating therewith, a second armature cooperating with the magnetic field produced both by said coil and by the first armature. and a retarding device cooperating with said first armature comprising a float connected to said armature, a chamber containing liquid in which said float operates, a reservoir connected to said chamber through a restricted passage, a check valve in the connection between said ehamber and reservoir permitting free flow of the liquid only from said reservoir to said chamber, and an overflow connection between said chamber and said reservoir.

3. Tn a time-limit device, a retarding device comprising a float, a chamber containing liquid in which said float operates, a reservoir connected to said. chamber through a restricted passage, and a float Within said reservoir having a limited upward movement when the liquid in said reservoir rises owing to lowering of the float in the chamher.

4. In a time-limit device, a retarding device comprising a float, a chamber containing liquid in which said float operates, a reservoir connected to said chamber through a restricted passage, a check valve in the connection between said chamber and said reservoir permitting free flow of the liquid only from said reservoir to said chamber, a displacement piston in said reservoir for regulating the level of the liquid, and a float in said reservoir having a limited upward movement when the level of the liouid in said reservoir rises owng to lowering of the float in the chamber 5. A time element control having a coil and an armature which is influenced by a magnetic field created by the coil, and a retarding device in cooperative engagement with the armature, such retarding de ice including a float, and a reservoir, the reservoir partly encircling the coil.

(3. A time element control having a coil and an armature which is influenced by the magnetic field created by the coil and a retar-ding device in coiiperative engagement with the armature, such retarding device inchiding a float and a reservoir, and means acting on the liquid in the reservoir to vary the buoyancy of the float.

7. A time element control having a coil and an armature which is influenced by a magnetic field created by the coil and a retarding device in cooperative engagement with the armature, such retarding device including a float and a reservoir, the reservoir partly encircling the coil, and having a curved liquid passage.

8. A time element control having a coil and an armature which is influenced by the magnetic field created by the coil, and a retarding device in cooperative engagement with the armature, such retarding device in cluding a float, and a reservoir having a horizontal bottom chamber, a vertical oat chamber freely connected to said horizontal bottom chamber, a restricted and controllable outlet from the bottom chamber, a governing float chamber, a vertical chamber communicating with the governing float chamber and a non-return valve between the vertical chamber and the horizontal chamber.

9. A time element control having a coil and an armature which is influenced by the magnetic field created by the coil and a retardin device in cooperative engagement with tie armature, such device including a reservoir and a float; the said float being open at the top and closed at the bottom and having a rod which is connected to the armature and passes into the float, the'said rod having a pin at its lower extremity engaging in a socket at the lower end of the float.

10. A time element control having a coil and an armature which is influenced by the magnetic field created by the coil and the retarding device in cooperative engagement with the armature, such retarding device including floats and a reservoir, the armature being hollow with a flange at the upper end, a ring engaging with the flange and having cars, a cross-head, bolts on the crosshead engaging with the ears, rods on the ends of the cross-head engaging with the floats.

11. A time element control having a coil and an armature which is influenced by the magnetic field created by the coil and the retarding device in coi perative engagement with the armature, such retarding device including floats and a reservoir, the armature being hollow with a flange at the upper end, a ring engaging with the flange and having cars, a cross-head, bolts on the crosshead engaging with the cars, rods on the ends of the crosshead engaging with the floats, and a staple on the cross-head, and. passing over an car.

12. A time element control having a coil and an armature which is influenced by the magnetic field created by the coil and a retarding device in cooperative engagement with the armature, such retarding device including a float and a reservoir, the armature being of tubular shape, a tube within the armature, a bracket supporting the upper end of the tube, a second armature within the tube, the said second armature being hollow and closed at the lower end, and a .rod entering the second armature and passing through the tube and bracket.

13. A tune element control having a coil and an armature which is influenced by the magnetic field created by the coil and a retarding device in cooperative engagement with the armature, such retarding device including a float and a reservoir, the armature being of tubular shape, armature, a bracket supporting the upper end of the tube, a second armature within the tube, and a rod entering the second armature and passing through the tube and bracket, and a bushing supported by the bracket and guiding the upper end of the rod.

14-. A time element control having a coil and an armature which is influenced by the magnetic field created by the coil and a retarding device in cooperative engagement with the armature, such retarding device including a float and a reservoir. the armature being of tubular shape, a tube within the armature, a bracket supporting the upper end of the tube, a second armature within the tube, and a rod entering the second armature and passing through the tube and bracket.

15. A time element control having a coil and an armature which is influenced by the magnetic field created by the coil and a retarding device in cooperative engagement with the armature, such retarding device including a float and a reservoir, the armature being of tubular shape, a tube within the armature, a bracket supporting the upper end of the tube, a second armature within a tube within the cluding a float and a reservoir, there being an opening in the reservoir, a transparent cover for the opening and a scale adjacent to the opening.

This specification signed and witnessed this 5th day of F eby., 1909.

CHARLES S. VAN NUIS.

the tube, the said second armature being hollow and closed at the lower end, and a rod entering the second armature and passing through the tube and bracket, and a bushing supported by the bracket and guiding the upper end of the rod.

16. A time element control having a coil and an armature which is influenced by the magnetic field created by the coil, and a retarding device in cooperative engagement with the armature, such retarding device in- Witnesses:

LEONARD H. DYER, JOHN L. LOTSOH.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, D. C. 

